Apr 16, 2013 1:00pm PDT
. and for the very latest on the investigation, we're joined now by nbc news justice correspondent pete williams from washington. so, pete, the very latest on the pressure cooker scenario that you're hearing? >> right. as you say, used for decades in terms of building bombs, so that's not going to be an area of inquiry that will immediately lead them in a certain direction, because the instructions, unfortunately, for making these devices are all over internet. just last month, the al qaeda online magazine "inspire" repeated an article that showed how to build pressure cooker bombs. so they've been out there for a long time. the part, the components of this device appear not to be very fancy. in addition to that, there were shrapnel, ball bearings, bbs, from the sound of the doctors you heard at the beginning of your program, apparently nails as well. and then for the explosive basically gun powder, smokeless powder that's commonly available in sporting goods stores. so all these pieces are easily available. some kind of timer as well. then placed in black sacks and put in two different spots. so wha
Apr 16, 2013 11:00pm PDT
decades for the fbi to locate and arrest the unabomber, ted kaczynski. within the last hour nbc news has confirmed a letter bomb -- not a letter. i should say a letter that tested positive for ricin or some other toxic substance was addressed to senator roger wicker of mississippi. it was intercepted before reaching the senator's office. let's begin this hour with nbc justice correspondent pete williams and former cia counterterrorism director larry johnson. two best guests we could have. pete, let's go back to that picture we just saw from whdh up there, boston affiliate of nbc. what are the experts making of the fact that it was there, that bag, whatever it is sitting there before the explosion and then in this picture taken afterwards you can see the smoke trailing up to the left there diagonally? what does that tell us? >> it tells us it's something they're investigating, chris. they know, they believe very strongly that the bombs were brought to the scene in backpacks. but i think it's fair to say they're looking at whether after they got there, they put them in these shopping bags.